Security ink pigment, security ink, printed matter, and method of producing security ink pigment

Abstract

Security of a printed matter is enhanced, a coat printed on a matter to be printed for a security enhancement of the printed matter is printed by a normal printing process, and the coat is flattened and smoothed. A security ink pigment contains a powder. A main constituent of the powder is a perovskite-type oxide. The perovskite-type oxide has a composition expressed as a general formula of ABO 3 . A is mainly made of Ba. B is mainly made of Sn. A median diameter of the powder is equal to or smaller than 10 μm. The powder emits infrared fluorescence when being irradiated with ultraviolet excitation light.

1 . A security ink pigment, comprising
 a powder having a main constituent of a perovskite-type oxide which is expressed as a general formula of ABO 3 , A being mainly made of Ba and B being mainly made of Sn, having a median diameter equal to or smaller than 10 μm, and emitting infrared fluorescence when being irradiated with ultraviolet excitation light.   
     
     
         2 . The security ink pigment according to  claim 1 , wherein
 the powder has a specific surface area ranging from 0.079 m 2 /g to 16 m 2 /g.   
     
     
         3 . The security ink pigment according to  claim 1 , wherein
 the perovskite-type oxide has a crystal lattice constant having a difference equal to or smaller than 0.002 angstrom from a theoretical crystal lattice constant of the perovskite-type oxide having a composition expressed as a composition formula of BaSnO 3 .   
     
     
         4 . The security ink pigment according to  claim 1 , wherein
 the perovskite-type oxide which is expressed as the general formula of ABO 3 , A being mainly made of Ba and B being mainly made of Sn, has a composition expressed as a general formula of Ba 1-x SnZn x O 3 , x satisfying 0≤x≤0.2.   
     
     
         5 . A security ink, comprising:
 the security ink pigment according to  claim 1 ; and   a vehicle by which the security ink pigment is dispersed.   
     
     
         6 . A printed matter, comprising:
 the security ink pigment according to  claim 1 ;   a material to be printed; and   a vehicle solid firmly fixing the security ink pigment to the material to be printed.   
     
     
         7 . A method of producing the security ink pigment according to  claim 1 , comprising:
 preparing a powder having a main constituent of a perovskite-type oxide which is expressed as a general formula of ABO 3 , A being mainly made of Ba and B being mainly made of Sn; and   performing a classification or a wet dispersion on the powder.